A portable computer, e.g., a notebook personal computer (PC) or a PDA (personal digital assistant), includes a communication function with respect to various kinds of networks. In a portable computer that is driven by a battery when taken along, saving the power consumption of the battery is one technical problem. As one technique of saving the power consumption in the portable computer, there is a technology of defining a plurality of power supply segments associated with use states to control power consumption. In some of the portable computers, for example, power supply segments, e.g., a system OFF state where an AC adapter is not connected (which will be referred to as a first OFF state hereinafter), a system OFF state where the AC adapter is connected to charge the battery (which will be referred to as a second OFF state hereinafter), a suspend state where the power is supplied only to devices required to store data in a main memory, or a system ON state where the power is supplied to all devices (which will be simply referred to as an ON state hereinafter) are defined, and any one of these segments is selected in accordance with a use state to supply the power to the respective devices constituting the portable computer. Therefore, although a wireless module used for wireless communication is also classified into any power supply segment, wireless communication is not usually carried out in states except the ON state, and hence the power supplied to the wireless module is stopped.
In order to start wireless communication when the portable computer is in the first or second OFF state, a user must operate the wireless module to search for a first connectable access point. To perform this operation, the computer must be turned on and BIOS must terminate an activation routine to start up an operating system (which will be referred to as an OS hereinafter). This takes time, and a CPU or a hard disk drive in which a power consumption is relatively high must be operated. Therefore, the user must carry out a troublesome operation to search for the access point, and a large amount of power is also consumed. Even if the user turns on a power supply of the computer to operate the wireless module in order to effect wireless communication, when an appropriate access point cannot be found, this purpose is not achieved, and hence the operation and the power required to turn on a system are wasted.
As an example of technology for searching for an access point by using a portable computer, there is Horikoshi (Japanese Unexamined Patent Publication No. 2006-166242) which teaches a technology for adding an access detection button to a notebook PC in which power is not supplied to an access point detection circuit when a power supply is in an OFF or suspend state, and supplying power to the access point detection circuit only when the access detection button is pushed, thereby performing scanning.
Further, as an example of technology for controlling power consumption in a wireless communication terminal, there is Takeshi (Japanese Unexamined Patent Publication No. 2002-176388) which teaches a technology for detecting that a display section case of a notebook PC is closed by using a switch to suppress an electric wave emitting operation of a wireless device or Shigeki (Japanese Unexamined Patent Publication No. 2002-229684) which teaches a technology for detecting a closed state of a lid of a portable mail terminal to stop the supply of power, thereby stopping reception of mail.
As taught in Horikoshi (Japanese Unexamined Patent Publication No. 2006-166242) since the power is supplied to the access point detection circuit only when an access point is to be scanned, the power can be economized. However, a case of the portable computer is small, and assuring a space where the button is newly provided is difficult, which results in an increase in cost. Furthermore, an antenna of the portable computer is disposed at a periphery of a display section integrated with a lid, and the antenna is usually designed in such a manner that a reception sensitivity for electric waves becomes most excellent when the lid is opened from a system main body and there is no interference from the system main body. When the button is provided to supply the power to the access point detection circuit, the lid is usually closed to search for an access point in a state where the reception sensitivity for electric waves is low. Therefore, even if the access point can be actually detected by opening the lid, detection is impossible in some cases.
While the above systems and methods allow for detecting wireless access points, a need has arisen for detecting wireless access points while overcoming the shortcomings discussed above.